Margin of Error: n = 1000, p = 0.2, 95% Confidence
For a 1000-person survey with a 20% expected proportion at 95% confidence, the margin of error is approximately ±2.5%.
How to use this tool
- Enter sample size (n), proportion (p) and z* (confidence level) in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your margin of error and the full breakdown beneath it.
Calculate the margin of error when the expected proportion of positive responses is 20%, such as in a product adoption or niche preference poll.
Frequently asked questions
- What is the margin of error?
- The margin of error quantifies the uncertainty in a sample proportion estimate. A MOE of ±3% at 95% confidence means the true proportion is within 3 percentage points of the observed proportion 95% of the time.